Toilet paper holder and towel rack removal

Member

I have ceramic paper towel holder and towel rack which I would like to remove and use somewhere else. They are probably original installed by the builder. They look like they are sticking to the wall, but how do I figure out if they are the type going into the drywall or just glued to the surface before I take them out? If they go into the drywall I would rather leave them where they are. If they are surface glued to the wall what is the best way to get them off?
Thanks.